The term machining refers to any one of a variety of processes in which a piece of raw material (a “workpiece”) is cut into a desired, final shape and sized by a controlled material removal process. In a typical machining process, one has a machine that includes a driver that induces usually a rotary motion or a linear motion to a tool. The tool then engages a work piece upon which the machining operation is to be performed. The engagement of the tool with the workpiece causes material to be removed from the workpiece.
In most cases, a rotary electric motor is coupled to a tool to move the tool in a rotary manner so that sharp edges formed on the tool, can cut into and through, the material of the workpiece.
Machining operations as described above have been in common use in industry for quite some time.
A tool holder is interposed between the driving motor and the cutting tool to couple the cutting tool to the driving motor. Typically, a tool holder has a first end that is coupled to the electric rotator, that may comprise a small electric motor (or a shaft of some sort), and a second end which holds the tool itself. The second end of the tool holder is usually designed to removably receive the cutting tool so that cutting tools can be conveniently coupled to and removed from the holder.
The most common type of machining is a milling operation wherein a machining device is used to rotate a cutting tool to cause the cutting edges of the tool to bear against a workpiece. Additionally, drilling operations are another type of machining operation in which holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the workpiece.
A different type of machining operation is a turning operation. A turning operation differs from a milling operation. A turning operation normally involves the workpiece being rotated rather than the cutting tool being rotated.
In earlier applications that are also assigned to the assignee of the instant invention, tool holders and assemblies and methods of modulation were disclosed that incorporated a linear, back-and-forth type oscillating movement into an otherwise rotary machining operation, so that the workpiece, would not only rotate with respect to the cutting tool, but would move in a linear fashion with regard to the cutting tool. In this regard, the reader's attention is directed to James B. Mann et al., U.S. Pat. Nos. 7,587,965; 7,628,099; 7,895,872; 7,617, 750; and 8,694,133.
The above patents disclose that modulation tool holder assemblies and methods of modulation involving a combination of linear and rotational movement of a workpiece can improve machining performance and/or create machine chip particles with controlled size and shape. The systems described in the above-referenced patents help to demonstrate the modulated cutting velocity or undeformed chip thickness can benefit the machining operations.
The devices described above disclose the use of stationary system for modulation that involved the rotation of the workpiece. These systems have demonstrated remarkable success in the ease of installation for processes where undeformed chip thickness is modular. The process relies on a linear oscillation motion that is super imposed on a non-rotating system. Another publication of interest is James B. Mann et al., U.S. Published Patent Application No. 2014/0241821 that discloses a tool holder that is capable of modulated movement in a rotating spindle. All of the above referenced Mann patents and publications are incorporated fully by reference into this instant application.
Although the device described in the '821 Published Application performs its function in a workmanlike manner, room for improvement exists. In particular, the device shown in the '821 application is somewhat complicated to install into an existing machine, and may require a range of modifications to the machine tool.
The above described device does provide some difficulties, when used on systems that rely on automated systems for tool changing, because the linear actuator or electrical power occurs across a rotating system.
One object of the present invention is to provide a device that improves over the devices described above.